Answer
$\frac{5}{36}$
Work Step by Step
P(E) = $\frac{no.\ of\ outcomes\ in\ favor}{Total\ no.\ of\ outcomes}$
A single die is rolled twice. The 36 equally likely outcomes are shown in the attached picture.
E: two numbers whose sum is 6
Favorable outcomes= {(1,5),(2,4),(3,3),(4,2),(5,1)}
P(E) = $\frac{5}{36}$